Validation of a multipoint near-infrared spectroscopy method for in-line moisture content analysis during freeze-drying.

•In-line moisture content analysis method for freeze-drying process was validated.•Method was based on multipoint NIR spectroscopy and quantitative PLS modeling.•Validation was performed using accuracy profile concept.•Method resulted in valid moisture predictions at the latter stages of the process.•Method can be utilized in pharmaceutical freeze-drying research and development.